Medical data, stored in electronic data bases comprises a large and heterogeneous category of information on individual patients, and is useful for managing treatment of individuals, administering healthcare and insurance systems, and medical research. Access to such data is ordinarily restricted by law or regulation.
The characteristics, format, and method of storage of such data differs amongst institutions, geographical areas, health care plans, countries, and the like, to the extent that few aspects of the data storage are fully standardized. That is not to say that efforts are not being made to achieve such standardization of format, for example in the DICOM (digital communications in medicine) standard, or others, however many records in physicians offices are still kept in paper format, or in legacy formats that are not interoperable with the presently available digital data formats used by hospitals, for example. Thus, the capability for the entry and retrieval of data regarding patient medical history, test results, existing medications, care plans, and the like, is limited. Some data is not accessible, and others may require the use of specific forms which may not be generally distributed.
From an evolutionary viewpoint, the types and formats of data that may be stored may change with time as the state of medical knowledge advances. New types of data, for example from different imaging modalities, or other diagnostic tests may be obtained for existing patients. Newly discovered relationships between various test results and syndromes may be identified as suitable for diagnostic purposes, and update treatment protocols may require access to data from differing time frames or differing data bases.
Generally, data bases are in a form known as relational data bases, and at present the most common data base query and maintenance language is SQL, or a variant thereof. When data is being transmitted over a telecommunications network, such as the Internet, data may be represented in XML (extensible markup language), which provides structuring and formatting for data which may be displayed on a web page. The data used to format and display information on a web browser page is HTML. For predetermined forms used for data entry and management, the PDF format (portable document format) may be used.
Particularly when retrieving data from a remote data base, the lack of particularity in the formatted request may result in data being retrieved from the data base and transmitted which is substantially in excess of that actually needed by the user. This may also include the data needed to reconstruct the form. While the transmission capacity of data links continues to increase, so do the demands for transmission and, inevitably, at some point in a data network, a bottleneck develops.